Heat pumps



March 2, 1965 J. R. HARNlsH HEAT PUMPS Filed Oct. 22, 1965 United States Patentg O 3,171,262 PEA? PUMPS James R. Hamish, Staunton, Va., assigner to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Get. 22, 1963, Ser. No. 317,928 16 Claims. (Ci. 62-160) 'This invention relates to heat pumps using auxiliary liquid pumping means in addition to the usual refrigerant compressors, and using surge drums.

In large heat pumps such as are used for cooling or heatind indoor air, particularly those heat pumps in which the compressors are unloaded at reduced loads, it is known that auxiliary liquid pumping means are desirable for keeping multi-circuit heat exchangers when used as evaporators, lled with liquid, and for lifting liquid to the outdoor heat exchangers which usually are located above the remainder of the components, and that surge drums, also known as accumulators are desirable for receiving gas and unevaporated liquid from the heat exchangers operating as evaporators, for separating the gas from the liquid, and for storing the excess liquid.

This invention is such a heat pump in which liquid from the heat exchanger operating as a condenser is supplied through an expansion valve into the heat exchanger operating as an evaporator; in which a surge drum is used to receive the gas and unevaporated liquid from the heat exchanger operating as an evaporator; in which a liquid pump is used during heating operation only to lift liquid from the surge drum to the outdoor heat exchanger operating as an evaporator, and in which an inductor operated by refrigerant supplied into the indoor heat exchanger is used during cooling operation to supply liquid from the surge drum into the indoor heat exchanger operating as an evaporator.

By using the liquid pump only during heating operation, a ptunp can be selected to meet the heating requirements only, and operating costs, and pump cavitation problems are reduced.

An object of this invention is to improve the performance of large heat pumps.

Another object of this invention is to reduce the capital and operating costs of large heat pumps.

This invention will now be described with reference to the annexed drawings, of which:

FIG. l is a diagrammatic view of a heat pump ernbodying this invention, and

FG. 2 is an enlarged sectional view of the expansion valve of FIG. l.

A hermetic refrigerant compressor C, driven by an electric motor CM, is connected by discharge tube to a conventional four-Way reversal valve RV. The valve RV is connected by a tube 11 to an outdoor heat exchanger 12; by a tube 13 to indoor heat exchanger 14, and by a tube 16 to a surge drum 1'7. The valve RV is controlled by a conventional pilot valve 18 which is connected by a capillary tube 20 to one end of the valve RV, and is connected by a capillary tube 21 to the other end of the valve RV. The pilot valve is connected by a capillary tube 19 to the discharge tube 1G. A solenoid 23 adjusts the pilot valve 18 to admit discharge gas into one end or the other end of the reversal valve RV, to move the piston of the latter which is not shown, to its cooling position when the solenoid 23 is deenergized,

rand to its heating position when the solenoid 23 is energized.

The surge drum 17 is connected by tube 25 to the inlet of liquid pump P which is driven by an electric motor PM. The outlet of the pump P is connected by tube 26, check valve 27 and tube 28 to the outdoor heat ex- 3,171,252 Patented Mar. 2, 1965 changer 12. The surge drum 17 is connected by tube 31, check valve 32 and tube 33 to inductor 35. The inductor 35 is connected by tube 36 to the indoor heat exchanger 14, and is connected through check valve 40 and tube 41 to the outlet of expansion valve 42. The inlet of the valve 42 is connected through tube 44 and check valve 4S to tube 46 which connects with the tube 36. The outlet of check valve 47 is connected to the tube 28, and its inlet is connected to the tube 41. The outlet of the check valve 4S is connected to the tube 44. The inlet of check valve 49 is connected to the tube 28, and its outlet is connected to the tube 44.

The inductor 35 has a converging nozzle 5@ into which tube 51 connected to the outlet of the check valve 4t) discharges. The How of refrigerant from the surge drum 17 through the tube 31, the check valve 32 and the tube 33 is caused by the action of the inductor 35 to ow into the latter and into the heat exchanger 14 when the latter is operating as an evaporator.

The expansion valve 42, shown in detail by FIG. 2, has a diaphragm chamber 52 having a diaphragm 53 extending across its center. The center of the diaphragm is connected by piston rod 54 to valve piston 55 above a valve opening 56 in a partition 57 between the inlet and outlet of the valve 42. The diaphragm chamber above the diaphragm is connected by a small tube 60 to a thermal bulb 61 in contact with the tube 44. The bulb 61 contains the same refrigerant as is used in the refrigeration circuit. The diaphragm chamber below the diaphragm is connected by a small tube 63 to the interior of the tube 44. The valve 42 maintains a predetermined amount of subcooling which may be 10 F., at a condensing temperature of 100 F., in the liquid leaving the heat exchanger operating as a condenser. When the valve 42 is adjusted towards closed position, it backs up more liquid in the heat exchanger operating as a condenser to increase the amount of subcoollng.

The indoor heat exchanger 14 is of the shell-and-tube type, and has an inlet 76 and an outlet 71 for water to be chilled or heated, and which are connected through a pump 93 driven by an electric motor 94 to Vlocal heat exchangers 9d, one of which is shown. A fan 91 driven by an electric motor 92 moves indoor air to be cooled or heated, over the heat exchanger 9i).

A cooling control thermostat CT has a switch CTS which closes when the thermostat CT calls for cooling. The switch CTS is connected, when closed, to electric line L2, and by wire '73 to one side of outdoor fan relay OFR, the other side of which is connected to electric line L1. The relay OFR has a switch OFRS which closes when the relay OFR is energized. The switch OFRS is connected to the line L1, and by wire 74 to one side of the fan motor OFM, the other side of which is connected by wire 75 to the line L2. The switch CTSv is also connected by wire 76 to one side of compressor motor starter CMS, the other side of which is connected to the line L1. The starter CMS has a switch CMSS which closes when the starter is energized. The switch CMSS is connected to the line L1, and by wire 77 to one side of the compressor motor CM, the other side of which is connected by wire Si) to the line L2. The motors 92 and 94 are connected across the motor CM.

A heating control thermostat HT has switches HTS1 and HTS2 which close when the thermostat HT calls for heat. The switch HTS1 is connected across the switch CTS. The switch HTS2 is connected, when closed, to the line L2, and to one side of the solenoid 23, the other side of which is connected to the line L1. The switch HTSZ is also connected to one side of pump motor relay PMR, the other side of which is connected to the line L1. The relay PMR has aV switch PMRS 3 which closes when the relay PMR is energized. The switch PMRS is connected to the line L1, and is connected by wire 79 to one side of the pump motor PM, the other side of vwhich is connected to the line L2.

Air cooling operation When the'indoor thermostat CT calls for cooling, it closes its switch CTS which energizes the fan motor relay OFR which closes its switch OFRS energizing the fan motor OFM. At the same time, the closed switch CTS energizes the compressor motor starter CMS which closes its switch CMSS, starting the compressor motor CM. The solenoid 23 is deenergized at this time, and the `reversal valve RV is in its cooling position.

The compressor C supplies discharge gas through the tube 10, the reversal valve RV and the tube 11 into the outdoor heat exchanger 12 operating as a condenser. Liquid from the heat exchanger 12 flows through the tube 28, the check valve 49, the tube 44, the expansion valve 42, the tube 41, the check valve 4t), the tube S1, the inductor 35 and the tube 36 into the indoor heat exchanger 14 operating as an evaporator. At the same time, the iow of refrigerant through the tube 51 into the inductor 3S, induces, aided by the ow of gravity, the flow of liquid from the surge drum 17 through the tube 31, the check valve 32, the tube 33, the inductor 35 and the tube 36 into the indoor heat exchanger 14 for preventing it from becoming starved.

Gas and any unevaporated liquid from the indoor heat exchanger 14 ows through the tube 13, the reversal valve RV and the tube 16 into the surge drum 17 where the gas is separated from the liquid and ows through the suction tube and the motor CM to the suction side of the compressor C.

The expansion valve 42 varies the amount of liquid supplied from the outdoor heat exchanger 12 into the indoor heat exchanger 14 in accordance with variations in the amount of subcooling in the liquid leaving the outdoor heat exchanger.

Air heating operation When the indoor thermostat HT calls for heat, it closes its switches HTSl and HTS2. The now closed switch HTSI is in parallel with the now open switch CTS of the thermostat CT, and energizes the Jtan motor relay OFR and the compressor motor starter CMS, which closes their switches OFRS and CMSS respectively, and energize the fan motor OFM and the compressor motor CM respectively. The now closed switch HTSZ energizes the solenoid 23 which adjusts the reversal valve RV to its air heating position. At the same time, the switch HTSZ energizes the pump motor relay PMR which closes its switch PMRS and energizes the pump motor PM, starting the pump P.

Discharge gas from the compressor C flows through the discharge tube 10, the reversal valve RV and the tube 13 into the indoor heat exchanger 14 operating as a condenser. Liquid fromV the heat exchanger 14 ows through the tube 46, the check valve 45, the tube 44, the expansion valve 42, the check valve 47 and the tube 28 into the outdoor heat exchanger 12 operating as an evaporator. The pump P pumps liquid from the surge drum 17 through the tube 2S, the check valve 27 and the tube 2S into the outdoor heat exchanger 12 for preventing it from becoming starved.

Gas and any unevaporated liquid from the outdoor heat exchanger 12 Hows through the tube 11, the reversal valve RV and the tube 16 into the surge drum 17. Gas separated from the liquid within the surge drum 17 hows through the suction tube 30 and the compressor motor CM to the suction side'of the compressor C.

The expansion valve 42 varies the amount of liquid supplied from the indoor heat exchanger 14 into the outdoor heat exchanger 12 in accordance with variations in the amount of subcooling in the liquid leaving the indoor heat exchanger 14.

What is claimed is:

1. A heat pump comprising a refrigerant compressor, an indoor heat exchanger, an outdoor heat exchanger, resersal valve means, a surge drum, a discharge line connecting said compressor to said Valve means, a suction line connecting said surge drum to said compressor,

a third line connecting said valve means to said outdoor exchanger, a fourth line connecting said valve means to said indoor exchanger, a fth line connecting said valve means to said drum, said valve means in cooling position routing discharge gas from said compressor through said third line into said outdoor exchanger operating as a condenser, and routing gas and unevaporated liquid from said indoor exchanger operating as an evaporator through said fourth and fth lines into said drum, said valve means in heating position routing discharge gas from said compressor through said fourth line into said indoor exchanger operating as a condenser, and routing gas and unevaporated liquid from said outdoor exchanger operating as an evaporator through said third and fifth lines into said drum, means including expansion means connecting said exchangers for supplying liquid from the exchanger operating as a condenser into the Vexchanger operating as an evaporator, liquid pumping means connected to said drum and to said outdoor exchanger, means for operating said pumping means only when said outdoor exchanger is operating as an evaporator, and means separate from said pumping means for supplying liquid from said drum into said indoor exchanger when said indoor exchanger is operating as an evaporator.

2. A heat pump as claimed in claim 1 in which said separate means comprises an inductor operated by the flow of liquid from said expansion means into said indoor exchanger to induce the ow of liquid from said drum into said indoor exchanger.

3. A heat pump as claimed in claim 2 in which means responsive to the temperature and pressure of the liquid entering said expansion means is provided for adjusting said expansion means to maintain a predetermined amount of subcooling in the liquid leaving the exchanger operating as a condenser.

4. A heat pump as claimed in claim l in which means responsive to the temperature and pressure of the liquid entering said expansion means is provided for adjusting said expansion means to maintain a predetermined amount of subcooling in the liquid leaving the exchanger operating as a condenser.

" 5. A heat pump comprising a refrigerant compressor, an indoor heat exchanger, an outdoor heat exchanger, resersal valve means, a surge drum, a discharge line connecting said compressor to said valve means, a suction line connecting said drum to said compressor, a third line connecting said valve means to said outdoor exchanger, a fourth line connecting said valve means to said indoor exchanger, a fth line connecting said valve means to said drum, said valve means in cooling position routing discharge gas from said compressor through said third line into said outdoor exchanger operating as a condenser, and routing gas and unevaporated liquid from said indoor exchanger operating as an evaporator through said fourth and tifth lines into said drum, said valve means in heating position routing discharge gas from said compressor through said fourth line into said indoor exchanger operating as a condenser, and routing gas and evaporated liquid from said outdoor exchanger operating as an evaporator through said third -and fth lines into said drum, means including expansion means connecting said exchangers for supplying liquid from the exchanger operating as a condenser into the exchanger operating as an evaporator, a liquid pump connected to said drum and to said outdoor exchanger, an electric motor driving said pump, and means including a thermostat for adjusting said valve means to its heating position and for energizing said motor to start said pump.

6. A heat pump as claimed in claim 5 in which means separate from said pump is provided for supplying liquid from said drum into said indoor exchanger when said indoor exchanger is is operating as an evaporator.

7. A heat pump as claimed in claim 6 in which said separate means comprises an inductor operated by the flow of liquid from said expansion means into said indoor exchanger to induce the flow of liquid from said drum into said indoor exchanger.

8. A heat pump as claimed in claim 7 in which means responsive to the pressure and temperature of the liquid entering said expansion means is provided for adjusting said expansion means to maintain a predetermined amount of subcooling in the liquid leaving the exchanger operating as a condenser.

9. A heat pump as claimed in claim 5 in which means 6 responsive to the pressure and temperature of the liquid entering said expansion means is provided for adjusting said expansion means to maintain a predetermined amount of subcooling in the liquid leaving the exchanger operating as a condenser.

10. A heat pump as claimed in claim 9 in which means separate from said pump is provided for supplying liquid from said drum into said indoor exchanger when said indoor exchanger is operating as an evaporator.

References Cited by the Examiner UNITED STATES PATENTS 2,716,868 9/55 Biehn 62-160 3,067,590 12/62 Wood 62.4198 3,077,086 2/63 Japhet 62-324 ROBERT A. OLEARY, Primary Examiner.

WILLIAM WYE, Examiner. 

1. A HEAT PUMP COMPRISING A REFRIGERANT COMPRESSOR, AN INDOOR HEAT EXCHANGER, AN OUTDOOR HEAT EXCHANGER, REVERSAL VALVE MEANS, A SURGE DRUM, A DISCHARGE LINE CONNECTING SAID COMPRESSOR TO SAID VALVE MEANS, A SUCTION LINE CONNECTING SAID SURGE DRUM TO SAID COMPRESSOR, A THIRD LINE CONNECTING SAID VALVE MEANS TO SAID OUTDOOR EXCHANGER, A FOURTH LINE CONNECTING SAID VALVE MEANS TO SAID INDOOR EXCHANGER, A FIFTH LINE CONNECTING SAID VALVE MEANS TO SAID DRUM, SAID VALVE MEANS IN COOLING POSITION ROUTING DISCHARGE GAS FROM SAID COMPRESSOR THROUGH SAID THIRD LINE INTO SAID OUTDOOR EXCHANGER OPERATING AS A CONDENSER, AND ROUTING GAS AND UNEVAPORATED LIQUID FROM SAID INDOOR EXCHANGER OPERATING AS AN EVAPORATOR THROUGH SAID FOURTH AND FIFTH LINES INTO SAID DRUM, SAID VALVE MEANS IN HEATING POSITION ROUTIONG DISCHARGE GAS FROM SAID COMPRESSOR THROUGH SAID FOURTH LINE INTO SAID INDOOR EXCHANGER OPERATING AS A CONDENSER AND ROUTING GAS AND UNEVAPORATED LIQUID FROM SAID OUTDOOR EXCHANGER OPERATING AS AN EVAPORATOR THROUGH SAID THIRD AND FIFTH LINES INTO SAID DRUM, MEANS INCLUDING EXPANSIONS MEANS CONNECTING SAID EXCHANGERS FOR SUPPLYING LIQUID FROM THE EXCHANGER OPERATING AS A CONDENSER INTO THE EXCHANGER OPERATING AS AN EVAPORATOR, LIQUID PUMPING MEANS CONNECTED TO SAID DRUM AND TO SAID OUTDOOR EXCHANGER, MEANS FOR OPERATING SAID PUMPING MEANS ONLY WHEN SAID OUTDOOR EXCHANGER IS OPERATING AS AN EVAPORATOR, AND MEANS SEPARATE FROM SAID INDOOR FOR SUPPLYING LIQUID FROM SAID DRUM INTO SAID INDOOR EXCHANGER WHEN SAID INDOOR EXCHANGER IS OPERATING AS AN EVAPORATOR. 